/*! \file vdr_decoder_flac.c
 *  \ingroup vdr
 *
 *  The file implements a decoder which is used by the player to decode flac audio files.
 *
 *  Based on code from
 *  MP3/MPlayer plugin to VDR (C++)
 *  (C) 2001-2003 Stefan Huelswitt <huels@iname.com>
 */

#ifdef HAVE_FLAC

#include <cstring>
#include <string>
#include <stdlib.h>
#include <stdio.h>

#include "mg_tools.h"

#include "vdr_decoder_flac.h"

#if !defined FLACPP_API_VERSION_CURRENT || FLACPP_API_VERSION_CURRENT < 6
#define LEGACY_FLAC
#else
#undef LEGACY_FLAC
#endif

#include <mad.h>

using namespace std;

static const unsigned MAX_RES_SIZE = 16384;

// --- mgFlacDecoder -------------------------------------------------------------

mgFlacDecoder::mgFlacDecoder( mgItemGd *item )
: mgDecoder( item ), FLAC::Decoder::File() {

	m_filename = item->getSourceFile();
	m_pcm = 0;
	m_reservoir = 0;

	initialize();
}

mgFlacDecoder::~mgFlacDecoder() {
	clean();
}

bool mgFlacDecoder::valid() {
	// how to check whether this is a valid flac file?
	return is_valid();
}

mgPlayInfo *mgFlacDecoder::playInfo(void) {
	return 0;
}

bool mgFlacDecoder::initialize() {
	bool state = true;

	clean();

	//  set_metadata_ignore_all();
	set_metadata_respond( FLAC__METADATA_TYPE_STREAMINFO );

	m_first = true;
	m_reservoir_count = 0;
	m_current_time_ms = 0;
	m_len_decoded = 0;
	m_index = 0;
	m_pcm   = new struct mad_pcm;

	// init reservoir buffer; this should be according to the maximum
	// frame/sample size that we can probably obtain from metadata
	m_reservoir = new FLAC__int32*[2];
	m_reservoir[0] = new FLAC__int32[MAX_RES_SIZE];
	m_reservoir[1] = new FLAC__int32[MAX_RES_SIZE];

#ifdef LEGACY_FLAC
	set_filename( m_filename.c_str() );
	FLAC::Decoder::File::State d = init();
#else
	FLAC__StreamDecoderInitStatus d = init( m_filename.c_str() );
#endif
	if (d) {
		mgError("FLAC: init() returns %d",d);
		return false;
	}
	process_until_end_of_metadata();

	return state;
}

bool mgFlacDecoder::clean() {
	m_playing = false;

	delete m_pcm;
	m_pcm = 0;

	if( m_reservoir ) {
		delete[] m_reservoir[0];
		delete[] m_reservoir[1];
	}
	delete[] m_reservoir;
	m_reservoir = 0;

	// why false? true?
	return true;
}

bool mgFlacDecoder::start() {
	bool res = false;
	lock(true);

	// can FLAC handle more than 2 channels anyway?
	if( m_item->getChannels() <= 2 ) {
		m_playing = true;
		res = true;
	}
	else {
		mgError( "ERROR: cannot play flac file %s: more than 2 channels", m_filename.c_str() );
		clean();
	}

	unlock();
	return res;
}

bool mgFlacDecoder::stop(void) {
	lock();
	finish();

	if( m_playing ) {
		clean();
	}
	unlock();

	return true;
}

struct mgDecode *mgFlacDecoder::done( eDecodeStatus status ) {
	m_ds.status = status;
	m_ds.index  = m_index;
	m_ds.pcm    = m_pcm;

	unlock();					 // release the lock from Decode() !

	return &m_ds;
}

struct mgDecode *mgFlacDecoder::decode() {
	m_decode_status = dsPlay;

	const unsigned SF_SAMPLES = (sizeof(m_pcm->samples[0])/sizeof(mad_fixed_t));

	lock(true);					 // this is released in done()

	if( m_playing ) {
								 // from database
		m_pcm->samplerate = m_item->getSampleRate();
								 // from database
		m_pcm->channels   = m_item->getChannels();

		// if there is enough data in the reservoir, don't start decoding
		// PROBLEM: but we need a first time!
		bool finished;
		if( m_first ) {
			finished = false;
			m_first  = false;
		}
		else {
			finished = m_reservoir_count >= SF_SAMPLES;
		}

		while( !finished ) {
								 // decode single frames until m_reservoir_count >= SF_SAMPLES or eof/error
			m_first = false;

			// decode a single sample into reservoir_buffer (done by the write callback)
			process_single();
#ifdef LEGACY_FLAC
			if (get_stream_decoder_state()==FLAC__STREAM_DECODER_END_OF_STREAM)
#else
				if (get_state()==FLAC__STREAM_DECODER_END_OF_STREAM)
#endif
			{
				m_decode_status = dsEof;
				finished = true;
			}

			// check termination criterion
								 // or error?
			finished |= m_reservoir_count >= SF_SAMPLES || m_len_decoded == 0;
		}

		// transfer min( SF_SAMPLES, m_reservoir_count ) to pcm buffer

		int n = ( SF_SAMPLES <= m_reservoir_count )? SF_SAMPLES: m_reservoir_count;

		m_pcm->length = n;
		m_index = m_current_time_ms;

		// fill pcm container from reservoir buffer
		FLAC__int32 *data0 = m_reservoir[0];
		FLAC__int32 *data1 = m_reservoir[1];

		mad_fixed_t *sam0 = m_pcm->samples[0];
		mad_fixed_t *sam1 = m_pcm->samples[1];

		// determine shift value for mad_fixed conversion
		// TODO -- check for real bitsize and shift accordingly (left/right)
		const int s = MAD_F_FRACBITS + 1 - ( sizeof(short)*8 );
		// const int s = ( sizeof(int)*8 ) - 1 - MAD_F_FRACBITS;      // from libsoundfile decoder

		if( m_pcm->channels > 1 ) {
			for( int j=n; j > 0 ; j-- ) {
				// copy buffer and transform (cf. libsoundfile decoder)
				*sam0++ = (*data0++) << s;
				*sam1++ = (*data1++) << s;
			}
			// "delete" transferred samples from reservoir buffer
			memmove( m_reservoir[0], m_reservoir[0] + n, (m_reservoir_count - n)*sizeof(FLAC__int32) );
			memmove( m_reservoir[1], m_reservoir[1] + n, (m_reservoir_count - n)*sizeof(FLAC__int32) );
		}
		else {
			for( int j=n; j > 0 ; j--) {
				*sam0++ = (*data0++) << s;
			}
			memmove( m_reservoir[0], m_reservoir[0] + n, (m_reservoir_count - n)*sizeof(FLAC__int32) );
		}
		m_reservoir_count -= n;

		// and return, indicating that playing will continue (unless an error has occurred)
		return done( m_decode_status );
	}

	return done(dsError);
}

::FLAC__StreamDecoderWriteStatus
mgFlacDecoder::write_callback(const ::FLAC__Frame *frame,
const FLAC__int32 * const buffer[]) {

	// add decoded buffer to reservoir
	m_len_decoded = frame->header.blocksize;
	m_current_samples += m_len_decoded;
								 // in milliseconds
	m_current_time_ms += (m_len_decoded*1000) / m_pcm->samplerate;

	// append buffer to m_reservoir
	if( m_len_decoded > 0 ) {
		memmove( m_reservoir[0] + m_reservoir_count, buffer[0], m_len_decoded*sizeof(FLAC__int32) );

		if( m_pcm->channels > 1 ) {
			memmove( m_reservoir[1] + m_reservoir_count, buffer[1], m_len_decoded*sizeof(FLAC__int32) );
		}

		m_reservoir_count += m_len_decoded;
	}
	else {
		m_decode_status = dsEof;
	}

	return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
}

void mgFlacDecoder::metadata_callback( const ::FLAC__StreamMetadata *metadata ) {
	// TODO not needed since metadata is ignored!?

	if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO) {
		m_nTotalSamples = (long)(metadata->data.stream_info.total_samples & 0xfffffffful);
		m_nBitsPerSample = metadata->data.stream_info.bits_per_sample;
		m_nCurrentChannels = metadata->data.stream_info.channels;
		m_nCurrentSampleRate = metadata->data.stream_info.sample_rate;
		m_nFrameSize = metadata->data.stream_info.max_framesize;
		m_nBlockSize = metadata->data.stream_info.max_blocksize;

		// m_nCurrentSampleRate = (int)get_sample_rate();
		m_nCurrentChannels = (int)get_channels();
		m_nCurrentBitsPerSample = (int)get_bits_per_sample();
		m_nBlockAlign = (m_nBitsPerSample / 8) * m_nCurrentChannels;
		m_nLengthMS = m_nTotalSamples / m_nCurrentSampleRate;
		m_nLengthMS *= 1000;

		// m_nAverageBitRate = ((m_pReader->GetLength() * 8) / (m_nLengthMS / 1000) / 1000);
		// m_nCurrentBitrate = m_nAverageBitRate;
	}
}

void mgFlacDecoder::error_callback( ::FLAC__StreamDecoderErrorStatus status ) {

	// check status and return
	switch( status ) {
		case FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC:
		{
			m_error = "An error in the stream caused the decoder to lose synchronization";
		} break;
		case FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER:
		{
			m_error = "The decoder encountered a corrupted frame header.";
		} break;
		case FLAC__STREAM_DECODER_ERROR_STATUS_FRAME_CRC_MISMATCH:
		{
			m_error = "The frame's data did not match the CRC in the footer.";
		};
		default:
		{
			m_error = "Unknown error occurred.";
		}
	}

	// cout << "Error occured: " << m_error << endl;
	m_decode_status = dsError;
}

bool mgFlacDecoder::skip(int seconds, int avail, int rate) {
	lock();
	bool res = false;

	if( m_playing ) {
		float bufsecs = (float) avail / (float) (rate * (16 / 8 * 2));

		const long target_time_ms = ( ( seconds - (int)bufsecs ) * 1000) + m_current_time_ms;
		const double distance =  target_time_ms / (double)m_nLengthMS;
		const long target_sample = (unsigned)(distance * (double)m_nTotalSamples);

		if( target_sample > 0 ) {
			if( seek_absolute( (FLAC__uint64)target_sample) ) {
				m_current_time_ms = target_time_ms;
			}
			else {
				seek_absolute( 0 );
				m_current_time_ms = 0;
			}
			res = true;
		}
	}

	unlock();
	return res;
}
#endif							 //HAVE_FLAC